Flash Index

Attempting to quantify the visual appeal of a colorfully toned coin has baffled the experts for years.  One can often make a snap judgment of whether one likes the toning on a particular coin, but until now, quantifying that judgment has been an arduous task.  In 2012, I developed a system called the “Flash Index” that could numerically score the visual appeal of a colorfully-toned coin at its optimal viewing angle. 

How the Flash Index Works

Computation of the Flash Index begins by scoring the obverse and reverse individually in 10 separate categories, with each category providing a maximum of 10 points.  This gives a possible perfect score of 100.  One then divides the computed score by 10 to get the “Flash Index”, which is on a 0.0 to 10.0 scale in one-tenth increments, providing 100 gradations of scores.  This provides enough detail to make a more precise separation or ranking of the visual appeal of any coin. 

  A 1909 Lincoln with the Flash Index calculated as 9.4 out of 10.0, which is considered high-end, gold-class toning.

Since this is a system geared for colorfully-toned coins, 4 out of the 10 categories (40%) relate to nuances of the coins color.  The the rest of the coins surface is evaluated through 3 additional categories (30%).  Then distractions are evaluated in 2 categories (20%).  And finally 1 category (10%) is reserved for the third party grade.

The Flash Index Categories for Scoring:

  1. Group A: Color
    1. Impression
    2. Transition
    3. Coordination
    4. Credibility
  2. Group B: Surface
    1. Reflectivity
    2. Luster
    3. Gloss
  3. Group C: Distractions

    1. Speckles
    2. Spots
  4. Group D: Grade
    1. Grade

Once a coin is scored in the Flash Index system, it can then be placed in one of three Flash Index Tiers (Gold, Silver, or Bronze).  This acts as a quick way to broadly categorize Colorfully Toned Coins.  From my years of experience with this system, coins with a Flash Index in the Gold Class (9.0 to 10.0) are stunning visually and can command many multiples over Guide Price.  Silver Class coins (with a Flash Index of 8.0 to 8.9) are very nice and eye appealing and can command a small to moderate premiums over Guide Price.  Bronze Class coins (with a Flash Index of 7.0 to 7.9) are still interesting, but often still sell near guide due to eye-appeal distractions.  Finally, coins that score less than 7.0 often have major distractions and most toned collectors would have little interest.

Flash Index Tiers:

  1. Gold Class (Flash Index 9.0 to 10.0)
  2. Silver Class (Flash Index 8.0 to 8.9)
  3. Bronze Class (Flash Index 7.0 to 7.9)